Was that he was upset that he wasn't a starter and didn't think he would get enough playing time to impress NFL scouts.
That's just hearsay and may be a outright lie. I don't know.
But, if it is true, I have a hard time understanding his decision. He has two guys who will be future NFL draft picks in front of him. Like I said, the way we rotate linemen he would have gotten his chance to play. I don't see how leaving the team would help his goal of getting to the NFL.
It's probably best to hope that he just doesn't like football anymore. That's the only way this makes sense.